High-pressure pipe



, o.v M AER HIGH PRESSURE Pin:

vmed May v) 1923 MgyZQ g 1924.;A

aval

Patented May 20, 1924.

UNITED STATES- omTo MADER, or DESSAU, eiiiaivrania` Assieiiion To GuiaMania-'1 H Ueo JUNxiiRs, or DEssAfU, l

.HIGH-PRESSURE PIPE. I

Application filed May 7,

To all whom t 'may concern.' Y

Be it known thatI, ,OTTO MADER, a citizen of Germany, residing at Dessau, Germany, have invented certain new anduseful Improvements in High-Pressure Pipes,

of which thefollowing is a specification.

My invention relates to high-pressure pipes as well as to a method of making such` pipes, and to means yfor connectingl them with other pipes and the like, More especially my invention relates to pipes serving to conduct liquids or gasesl under high pressure and having a comparatively Vsmall, inner diameter. l l i Y While itis noty ydifficult to manufacture pipes for high pressures, forinstanceup to 1000 atmospheres, if theinner diameterV is solargethat the pipes can jbe drawnv over ,a mandrel or can be milled, it .hasrhitherto e been limpossible toproduce,'in-,amanner warranting reliability of operation, pipes of comparatively small inner diameter, such, :for instance, as :from l, to `5 mms., and capable; 'of withstanding apress'ure such as aboveinen- A tioned. Thereis a strong demand 'for-:ab i solutely. reliable high-pressure pipes of small dilameteigsuch pipes being required, .forinstance, for the fuel supplyv conduits of-,oil motors in which'the :fuel is made toy pass through the conduit undera very high pressure in orderl to affect a sufficientlyintimate atomization. The volumeof liquid con- 'tained in, such pipes should .be onlyy small as possible be subjectedto the'higli pressure, in order to prevent the controlof the injection from being aectedvby reasonjof the compressibility' 'of the liquidV fuel. v

The insuiicient resistivity of pipes with small inner diameter` is caused by' .the :inner wall of the pipe presenting small fissures resulting from the excessively high tension arising in the wall of the pipe while it is being made, these fissures getting larger frequently while the pipe is in use, or causing the pipe to tear up. These drawbacks cannot be obviated even by the use of comparatively thick walled pipes.

My invention provides a reliable highpressure pipe with small inner diameter i the following manner:

I provide a pipe the inner diameter of which is so great that the inner surface is sure to be free from lissures. In order to in'order that but as small a q uantityof oil 1323. f f-se'ri'aino.' Gamesa. il @aan ai@ requisitejaiaii "maar, diameter; other.- pipe having'V aboring of correspondingly @small inner, diameter is i inserted in the pipe', firstgmentioned and tlie two pipes are then brought into intimate contact, whereby the outer pipewith'its superior mechanical 4strength is madeto takeV up part ofthe straintoiwhich thepinn'er pipe is exposed,`

especially f at those places where the inner pipe cannot withstand this strainv owing -to thessules. in .ifS Wallpreferred method of making th`e`compound pipe offfthe kind described is they followings'Ihe outerfpipathe inner surface Voff'vr'rl'iicli is, asa rule, not quitesniooth, nor. the section accurately circulanand'which is frequently kcovered ywith scale is, `first of all,

Gleansredi" mme@ Scrapers, ,preerablv `several Scrapers of.` yi n,creasingv diameter .which are 'applied'v one after', A another until the tube is sufficiently'. clean and smooth.

The inner diameter ofthe.oiiterfpipemustlbe V:so largethat it just permitsfpiishing thelin-v ner pipe. in.'v ','Ihe two-pipes are nowvdrlawn through several, drawmplatesL of decreasing l diameter yor the'comp'oundp'ipe isy caused" to kpass between `suitably grooved rolls, the ef- .,fect being in Veither Ycase that theV outer lpipe applies.itselfclosely tothe inner one.Y y j I prefer employing an outer pipe consist ing of ,steel of great sti'eng'th, whereas the inner pipe may consist of a softer: material, such, for in stanC.,as .iron for copper. -V

yIniordeiato, effect la;reliable. connection be- .tween ftwo such',compoundfpipes 'withv'each i 'other` orgwit-hmpart of an engine, such, fer instance, -asa pump cylinder or avalve casing orthe like, Vspecial means must beresorted to.v y"Iheus'ual manner of connecting aj pipe a` branch orother member `meansfofa `screw-tliread and by soldering is not free'from objections, asa connectie-nef this kind cannot easily be kept tight.

Accordiiigto my invention, I cause the inner pipe to extend farther into the branch or other jointing member than the outer pipe. In order to attain a tight connection, it is particularly useful to cause thev inner pipe to extend right through the j ointing member so that it projects from it, the projecting portion being cut olf only after the soldering has been effected.

In the drawings aiixed to this specification and forming part thereof my invention is illustrated diagrammatically by Way of example. In the drawings?- Figure 1l is a cross `section,jot aghighpres'sure V'compound pipe" according *to the 5 present invention, drawn to an yenlarged scale.

Figures 2, Ytions of connections for high-pressure compound pipes, drawn to natural size.v In Figure Yl b is the outery pipe manuactured so as to havea-smoothinner'sulface, andk c is the ,inner ,pipe .which .com- 4pletelyftills up the outer on e,'the diameter of the boring cof' the innerfpipebeingrom "l to mms. Theinn'ersurface of'lvvallof this boring 'pis rough, oryfuneyen and y.has cracks or" fissures, asindicatedfimthe draw- 111g Y v gure illustratesthe'moe 0f Gennading :the vend "of a `chompourrd "high-pressure ,pipe 'Withr'a ujointing '-nriember, :this connection being such as rordinarily Husedjtor connecting ordinarytubes. The end v'faces `ofthe pipes a;` `and terminate in. the same jlplane, andfthe entire ycompound .tube is Screwed at .into @.fSOCkeU-lkei J'Ontllmember d,jhav1ng aH narrow y'boring einalign- VV,ment with fthebor'ing 'c of ythe compound tube. lThis vinvolves the drawback .that the 30 annular spacebetvveen the end of lthepip'es ,c and b ,and Vthe kconnecting .member isfliable "11.01210 'be filled up' Wthss'oldeel'so that air can be retained. 'inv :this place `which Y may giverise'ito-serious troubles. This connection can pfbe, ;materi ally impr'ovedfby causing the inner'tube to project -beyond :the Outer ,weiland 'by fdorrpfone "ingly, shaping the innery end of the bore of the'jointingmember, as shown in Figure Y 4o The inner :tube afextendsgdeeperfinto the member d, whereby the joint'betvveenjthe inner end 'of the boring fe and the compound pipe is elongated and rendered correspond iRely tighter.

- .45 This connection, although being superior p kto the one illustrated' in kEfigurQ-LQ, involves Ia drawback which is due to the soldering. v VIt has y'been 'found' thatjthe liquid splder tends to enter the narroW'passages-eand c attheir point` of meeting, andto y'illzthem .upjvby capillary action. Itjis fditicultvto remove the solder by. boring, out, this4 procedure involving also the danger of A'renderin'g y'the Walls uneven. Y' Y f n V`offthepipeu is closed by almetal `pinh or 3, and 4 are longitudinalfsec- `surfaces-Withoutiloeing able to obstruct the -v pound tubes ofJsmall internalfdi'ameter,` con- In order to prevent this, I prefer employing the connection illustrated in Figure 4. flheginnergpipe-a heref, extends through the bottom-ofthe jointing vmember d so as to project beyond it, and the end of theV boring the like. The outer pipe b only extends to the inner surface of the bottom, The parts are thenffsoldered together and the solder can now flow through between the contacting e5 passage c, the connection hereby obtained being so perfect thatthe screw-thread f (Figs. n Zjand l3) may V be Vdispensed With entirely. After tlie-'soldering operation has been carried through, the projecting end of thefpipe 'a' is cut off.

I vvish'it to'be ,understood that Ido not desireto `be limited'to the' exact details of Aconstruction*shown and described, `Vfor ob- 'Vious `modifications 1 Will occur skilled in 4'the "art,

to ka person ""I`claim2-- f f y LFI-Iigh pressure tube of small internal diameter comprising in combination an inner capillary `tube having the desiredfdiameter,^an outer tube tightly drawn onto said inner tube and jointing piece surrounding the end ofthe compound tube, theV innerltube 'projectingfartherinto said jointingV Ipiece thantheouter tube, f and solder o'wed rinto' Vvthe j ointfbetvveensaidtube andthe jointi'ng' i "piece, il, v2. l.IcIighfpressure tubeV of -small internal 'diameter-comprising in combination an 'in- VnerI capillary tubefhavingtheV desired diameter, an vouter tubev tightly 'drawn onto vsaid l inner tubei andr a'jointing .piece surrounding the end o't the compound tube, means sealing lthe-tube to the jointingpieceytheIinnerftube 'projecting `farthervinto lsaid'jointing piece 95 A than the outer tube`l and projecting i through vthe bottom off'said jointing piece; Y

- `3. The-methodofmaking a joint on com-V` sisting in,` introducing such tube'into av joint-` ing-fpiece With'the inner part of 'said Stube 'projecting' onthe other side of said fjointing 'Y p1ece,^-introducing solder between said tubes andsaidfpiece andl cutting 0E the projecting end of'said innerpart. v 105 *In testimonywhereof'I atlixV my signature.

OTTOMADER. 

